1. Field of the Invention
This invention relates to apparatus for making a yarn comprising a device which succeeds a drawing frame and serves to twist a drawn roving and to wind covering fibers around the roving, and means for supplying the covering fibers.
2. Description of the Prior Art
From Austrian Patent Specification No. 361,814 it is known that a drawn roving can be twisted and covering fibers can be wound around said roving in a process in which the drawn roving is pulled through a generally triangular spinning space between two juxtaposed, closely spaced apart spinning drums, which rotate in the same sense, while air is sucked from said triangular space, and in which the roving is supplied with covering fibers in a direction which is transverse to the axis of the roving from a separate drawing frame through that spinning drum which rotates into the triangular spinning space. For this purpose, additional air is sucked from that spinning drum in a corresponding portion of its periphery so that the covering fibers are guided as they move on the surface of the spinning drum into the triangular spinning space and are wound around the partly twisted roving. Whereas the aligning of the covering fibers by means of a drawing frame and the guiding of the covering fibers on the spinning drum which rotates into the triangular spinning space contribute to an effective and uniform winding of the covering fibers around the roving, the result falls short of the expectations. For this reason the covering fibers have been supplied to the triangular spinnign space in a freely flying state although this gives rise to different problems owing to the aerodynamic conditions in the triangular spinning space.